The Italian peninsula is dominated by its upland regions, leaving only a small area for flatter ground. A number of these regions were significantly fertile (well-watered and low-altitude), but also according to recent research potentially unhealthy, since they were probably highly susceptible to malaria.20 The most prominent wider expanses within the area of republican Italy are the plains of the Tavoliere and Campania. Alluvial plains are more numerous on the Tyrrhenian coast, but usually hemmed in by hills and mountains. The most prominent are the Maremma and the Pontine plain. Most plains are simple strips, bordered by a beach of about 20-25 m asl. There is a major contrast between the two coasts. The Adriatic coast is composed principally of long, straight beaches, occasionally interrupted by headlands. The Gargano promontory and the cliffs of the Salentine peninsula are more dramatic. The Tyrrhenian coast is generally characterized by alternating headlands, smaller or larger embayments, and prominent lagoonal formations.2 To the north and the south, the coastline is more rocky.
The Tavoliere, the largest plain of peninsular Italy, covering some 7,000 sq km, is of interest for republican Italy because of the preservation of extensive settlement systems of the period and the connecting road systems based on centers such as Arpi and Lucera.22 The plain is formed out of a trough in the Apennine system, sitting astride the Bradano trench which runs parallel to the main Apennine range. Its area is defined by two rivers (the Fortore to the north and the Ofanto to the south) and surrounded on three sides by uplands (the Gargano and the Murge to the north and the south, the main Apennine range to the west), and on the fourth side by the sea. The basal limestone of the plain is covered by deposits of fine marine blue clay, followed by yellow clay. Erosion deposits are generally found on these basal levels. At first glance, the area is extremely flat, but as so often in such areas, more detailed examination reveals variations, in this case a series of terraces from 400 m asl down to 3-7 m asl near the sea itself. Within these areas, subtle differences in level can be extremely important for drainage; the river system has generally become more sluggish during the Holocene and in some areas a crosta or calcareous deposit has formed as a calcrete beneath the surface, which has helped preserve the form of any structures which cut through this level. The Tavoliere is a thus an area where environmental change can be appreciated, principally the product of upland erosion and coastal aggradation, processes which were particularly prominent from the end of the first millennium BC. Through a study of the location of Roman settlement and the examination of sections (e. g., at Marana di Lupara), it can be established that the coastal regions would have been much more lagoonal, open, indeed in part navigable, in Roman times. Sallares suggests that the Alpi area, a lagoonal area to the south would have been highly susceptible to malaria by late republican times.23
The Campanian plain is set within the characteristic ‘‘great limestone framework’’ encountered elsewhere in peninsular Italy. 4 The originality lies in its contents, which are frequently derived from volcanic action; a substantial part of the plain is based on volcanic ash; the Campi Flegrei are composed of small hills and craters, the product of volcanic activity close to the surface; the Baiae coastline has a lunar aspect; and the whole is, of course, dominated by deep-seated volcano of Vesuvius itself. The republican populations would have lived some 1,600 years after an eruption of similar scale (technically defined as ‘‘Plinian’’ after the Roman writer Pliny the Younger, who described the eruption) to the one that later engulfed Pompeii in ad 79.25 This major explosion 1,600 years before ad 79 was probably from a different summit (Somma antico), which is of recent formation. However, there were at least nine eruptions in the intervening years, of which three would have been of considerable proportions (defined by vulcanologists as sub-Plinian), and thus the resident populations should have been very aware of the presence and, to some extent, the danger of volcanic action. The last sub-Plinian explosion is dated to about 1000 BC and was followed by four smaller events which laid down thin, dark layers of ash, lapilli, and fine scoria. Study of the erosion of these deposits suggests that as much as 700 years may have elapsed since the last threatening volcanic activity by the time of ad 79, and thus the republican period lay in a period of quiescence, allowing considerable regrowth of vegetation.2 The Campi Flegrei and the associated promontory (Misenum) and islands (Prochyta [Procida], Vivara, and Pithecusae [Ischia]) represented a more constantly unstable landscape of changing land and sea levels, fumaroles, and springs, associated with classical myth. On Pithecusae there is evidence of the eighth-century BC settlement being engulfed by volcanic ash. Recent studies have shown the instability of the area by establishing the sequence of changes in land-surface level and earthquakes.27
The Maremma is one of the larger coastal plains of central Italy which is of interest to republican Italy because of the presence of colonies such as Cosa.28 It is another area chosen by Sallares to illustrate the potential ecology of malaria and, for him, provides a reason for the hesitant development of the colony.29 The northern part of the region is bounded by the Colline Metalifere, as the name suggests, an important metal ore zone, which projects into sea, with Elba at its maritime limits. The whole region is composed of four river basins: the largest, the Ombrone, the fourth largest of the peninsula, is accompanied by three smaller rivers, the Albegna and the Fiora to the south and the Bruna to north. The Albegna (67 km long in a catchment of 737 sq km) forms an important physiographic divide between northern and southern Etruria and is the most studied valley of the region.30 The valley was thus an important feature of the pre-republican political geography, providing a self-contained buffer zone and a means of communication into the interior. A prominent characteristic feature of the coastal margin of this river valley is the lagoon that runs from Ansedonia to Pescia Romana and the poor drainage promoted by sediment transport from up the valley which blocks the exit to the sea. The Romans attempted to solve these difficulties by means of an artificial cut. Another prominent feature is the high promontory of Monte Argentario, which protects the lagoon from the sea approaches. Behind the lagoons there are also some low, isolated hills which stand above the surrounding alluvial plain; together with a hill zone backing onto the high mountains, these complete the key ecological zones of the valley.
The Agro Pontino is a typical microregion circumscribed by the structural framework of the upland geology of the Italian peninsula.32 It is of interest to republican Italy, because this geographical region was encircled by the coloniae of Circeii (to the south), Satricum (to the north west), and Cora and Setia (to the northeast). It also provides Sallares with his principal study of the potential ecology of malaria in republican Italy.33 He even suggests that attempts to improve the ecology by Cornelius Cethegus in 160 bc actually improved the breeding conditions for the species of mosquito that carry the disease. To the northeast are the abrupt limestone mountains of the Monte Lepini and the Monti Ausoni. To the northwest are the volcanic deposits of the Latium complex. On the coast to the southeast are the sand and clay marine terraces headed by the limestone outcrop of Monte Circeo. In the middle is a depression filled with peat and clay, which the Romans tried to drain. Recent research has uncovered a complex sequence across the microregion of marine terraces covered locally by windblown material. The upper (25 m) Latina terrace consists of poorly drained lagoonal deposits and well-drained sandy beach deposits from the Middle Pleistocene. The Minturno terrace (16 m), dating to the last interglacial of the Late Pleistocene, comprises a fossil beach and a clayey lagoonal deposit. The Borgo Ermada terrace (6 m), dating to the last glacial of the Late Pleistocene, comprises well-drained sand beach deposits along side poorly drained clayey lagoonal deposits. The youngest Terracina terrace dating to the Holocene (the last 10,000 years) is placed just above modern sea level and combines coastal dunes with lagoonal deposits. Parts of this lower landscape were only reclaimed by Mussolini in his emulation of the ancestral Romans who made various attempts at reclamation. This is the location of extensive peat and clay peat deposits cut off from the sea by coastal terraces. Springs running down from the mountains have also produced travertine deposits. Detailed studies of different parts of the Pontine region have shown different rates ofalluviation and colluviation related both to the location in the landscape and the socioeconomic context of the sample zone.34 In the neighborhood of the republican town of Sezze, the pre-Roman landscape is separated from the republican by a sheet of colluvial sediment.
World History
